1. Field of the invention
The present invention relates to a system and a method of imaging.
2. Description of the Prior Art
Many modern videogame devices utilise a video camera to capture video images of a scene. Typically these are used to estimate user postures (for example in dance games), or to identify special objects within the captured scene, such as so-called fiduciary markers, which comprise high-contrast asymmetric patterns whose position and orientation within the video image can be uniquely determined.
In either case, the videogame device may then process the image to augment it for display on a TV or the like, for instance by overlaying a virtual object on the image of the user, or positioning a virtual object in the video image at a position and orientation consistent with that of the fiduciary marker.
However, the detection of such features within video images requires considerable data processing, and notably the amount of processing can vary depending on where in the scene the user of fiduciary marker is. This is primarily because the user or marker's location affects their size in the resulting video images and consequently the number of pixels that the videogame device must process.
This in turn makes the maintenance of video frame rates and the budgeting of available processing resources difficult, as the position of the user or marker is generally out of the videogame device's control.
In addition, tracking users or markers is made more complicated when some or all of the user or marker moves outside the field of view of the video camera, either because they have moved significantly within the scene or because they have got too close to the camera.
The present invention seeks to mitigate the above problems.